A new continuous-time stability perspective of time-delay control: Introducing a state-dependent upper bound structure

Spandan Roy, Jinoh Lee, Simone Baldi

Research output: Contribution to journalArticleScientificpeer-review

11 Citations (Scopus)

Abstract

In the literature of any time-delay control (TDC)-based methods, the boundedness of the error due to time-delay estimation (TDE) is crucial to prove the stability. However, the TDE error has been studied by discretizing the closed-loop system while neglecting the effect of discretization error; consequently, the TDE error is considered to be upper bounded by a constant. This paper proves that such constant upper bound is restrictive in nature due to the explicit involvement of system states in the TDE error. Thereby, without discretizing the closed-loop system, a new structure of the upper bound of TDE error is directly formulated in the continuous-time domain which has an explicit dependency on the system states. Via this formulation, this paper solves the long-standing problem for TDC of having consistent stability analysis and control design in continuous time. Based on the newly proposed structure of TDE error, an enhanced robust control law is formulated. The effectiveness of the proposed method is experimentally substantiated as compared to the conventional TDC using a multiple-degrees-of-freedom robot.

Original languageEnglish
Pages (from-to)475-480
JournalIEEE Control Systems Letters
Volume3
Issue number2
DOIs
Publication statusPublished - 2019

Keywords

  • Closed loop systems
  • Lyapunov Stability
  • Robots
  • Robust control
  • Robust Control
  • Stability criteria
  • Time-Delay Control.
  • Uncertainty
  • Upper bound

Fingerprint Dive into the research topics of 'A new continuous-time stability perspective of time-delay control: Introducing a state-dependent upper bound structure'. Together they form a unique fingerprint.

  • Cite this